The present invention relates generally to inkjet printing and, more particularly to inkjet printers having on line service stations having spittoons, wipers for wiping inkjet orifices and orifice caps for capping an array of nozzles on a printhead.
Conventional inkjet print engines contain three primary components which are generally organized in series. These components are the platen (including a print zone) the spittoon, in which excess print drops are disposed, and the service station where cartridge wiping and capping functions occur.
In a conventional inkjet print engine, there may be two or more ink cartridges, or printheads, mounted side by side on a transversing carriage which moves substantially perpendicular to the path of media, such as paper, which pass through the machine to be printed upon. Caps are used to prevent the cartridges from drying out during periods of non-use and they are spaced at a center to center distance of the cartridges, as the cartridges are mounted in the carriage, so that each cartridge can be simultaneously capped during periods of inactivity.
Wipers for cleaning the cartridge nozzles during servicing are often mounted on the same center to center distance of the cartridges mounted in the carriage. This allows the wipers to move in synchrony while simultaneously wiping the cartridges. This feature renders the wipers capable of being actuated by a common mechanism.
The spittoon can be one common receptacle for receipt of excess ink drops from the cartridges, although in some cases incompatibilities between inks has resulted in the use of separate spittoons.
In conventional inkjet printers, the three above described components are disposed linearly with a consequent unwanted increase in the width of the finished inkjet engine. In recognition of the problem presented by a wide system, an attempt at optimization, such as staggering the wipers between the caps, has been made. Even here, however, the width of the inkjet printer is the sum of service station width (comprised of capping width, plus one wiper, since the other wiper is disposed between the two caps) plus the platen (having a width at least equal to the width of the media to be printed upon), plus the width of the two spittoons.
As a limitation generally recognized in any attempt to optimize printer design, the spittoons should be located outside the platen area, or print zone, since, during printing the cartridges spit droplets at the same time a sheet of media is being printed on. The caps, on the other hand, can be inside the print zone since the cartridges require capping only during non-use.
With regard to printhead wiping during a print job, some conventional print engines have used a technique of wiping in the middle of the print job. As the carriage is driven to the side over the service station, cartridge wiping occurs after which the carriage is returned to the platen to continue printing on the media. While this approach may result a narrower print engine, such mid-page wiping is detrimental because of "wait banding". This is often seen as a white streak across the media caused by a difference in timing from print swath to print swath during the printing process.
Further, dimensional hygroscopic limitations may cause problems. This is seen especially in paper media, wherein time constants can cause a different amount of expansion in the print media, depending upon how long the previous swath has absorbed the ink deposited thereon. This difference of expansion can cause swath to swath advance errors between swaths with no wiping, as compared to swaths with wiping.
In view of the foregoing, it is apparent that there is a need for a narrower print engine which would consume less desk space for the user. Among advantages of such a narrower print engine would be shorter carriage travel over a shorter slider rod. This would result in a more efficient printer which would be sturdy in construction. Advantageously, such a printer would result in lower product weight and cost.
While the following detailed description relates to inkjet printers, it will be recognized that the principles set forth apply also to a number of small footprint devices, such as copiers, fax machines, scanners and combinations thereof.